Lubricating oil additive materials prepared by condensing alkyl halides with haloaromatic-aliphatic hydrocarbon copolymers



Patented July 15, 1 952 IDES: WITH HALOAROMATIC+ALIPHATIC HYDROCARBON COPOLYMERS John 1). Garber, Cranford, and David W. Young; Roselle, N. J., assignors to StandardOilDevelop'nient Company, a corporation of Delaware v No Drawing. Application March 0, 1948,

.SerialjNo. 13,536

This invention relates to novel oil compositions containing a particulartype of viscosity index improving agent, and more especially the invention relates to vminerallubricating oil compositions containing special high molecular weight copolymers of a lower olefin and a polymerlzable mono-olefinic haloaromatic compound; for example a copolymer of is'obutylene and parachlorstyrene.-

It has been known for some time (see USS. Patent 2,084,501) that isobutylenecan be polymerized at low temperatures,- eig; l C. to I00 C. or lower, by means of a Friedel-Crafts catalyst-such as BFa' or A1013, "tc'r'high molecular weight oil-soluble chain type polym'ers'havi-ng molecular weights ranging from 1000 to 400,000 or more, preferably about-5000 to 100,- 000 or so, which when dissolved in mineral lubricating oilg have the'property of increasing the V. I. (viscosity'index) thereof. One difliculty, however; with such polymers, is that they do not have a high enough viscosity index ceiling when added to parafiinic lubricating oils; for instance in a refined parafiinic lubricating oil base stock' having a V. I. of 112, a small amount of polybutene will'raise the V. I. up to about 135, the amount required being somewhat indirectly proportional to the molecular weight, but no" matter how much polymer is added, the viscosity 'indexcannot be raised above about 135, thisbeing'calledthe V. I. ceiling for polybu'tene blends in such aparaffinic oil base stock. 4

It has also been disclosed (in U. s Patent 2,274,749) that polymerizable aromatic] materials such as styrene may be copolymerized with isobutylene in the same'type of low temperature Friedel-Craftsprocss, and that the resulting copolymers may beused as viscosity index improvers for lubricating oils; however, the reported results'do notshowmuch improvement over simpleisobutylene polymers insofar as-V. I.- increa'sing effect is concerned. It has also been shown that a number of different types of polymers can be'fluorinated and the resulting products .addedt lubricating oils; however; many halogenated polymers are insoluble 'in lubricating oils, especially in paraffinio mineral lubricating oils; and most chlorinated 'aliphatic"poly mers have corrosive 'tendenci whe sed as lubricating oil additives. It has now been discovere lubricant'compositionsca ing with a 'mineral lubrieating bil bas'e stock a high molecular weight substantially" saturated that "aliiable 7' Claims. (Cl. 260-875) nfbe prepared by blend copolymer of a major proportion of .a'lower olefin such as isobutylene, with a minor propor tion of a polymerizable mono-olefinic' halo aromatic compound,such as chlorstyreneori a bromst rene f Several advantages I accrue; to, the halp en ated copolymer' as compared' with the unhalogenated product, disclosed in U. S. Patent 2,27%,749, For example, the halogenated 'prodnot is more soluble. Thus, itis possible'to hays a higher concentration of-eopolymerdn a 113 drocarbon oil 'with'oult "terbidityy Furthermore, due to thickening "effect of a "higher V'. I. ceiling as obtained with the halogenated product than with the unhalogenated product for algiven niolecularweight. p

Instead of isobutyle'ne; other iso-olefins may be used such "as isoamylene (particularly 2- methyl' butene l iso octylene} etc'l, as wen as other aliphatic o'lefins such as ethylenafpropyl ene," normal butylene,"octane-1,1"dodecene l; octadecene-Letc. As the halogensubstituted polymerizable aromatic ompound,' one mayuse' parachlor' styrene, parabromstyrene, parafluorstyrene, alpha' methyl parachlo'rstyrene; 'm'-'chlorstyr'ene', o-fluors tyrene," m -fluoi-styrene; or'- other" ni'oiiohalogen" substituted" styrene; or mi xedproducts containing an average of 1 about 1' halogen atom per molecule. Also, dih'alogen-substituted-sty renes maybe used, such as 2-5-dichlorstyrene, Z-S-dibronistyrene, 3-4-dichlorstyrene, or mixed products containing an average'of 2 'h'alogen atoms per molecule. small amounts oi tri-dor even higher halogen-substituted styren'es may be used. Other halogen'substituted polymerizable aromatic compounds may also be used, such as chlorindene, chlorinated dihydronaphthalen'e,'etc.-"' V W f Thepropor "o'ns of copolymerization reactants to be used, may be varied to some extent according to their nature-,b'ut generally the proportion of haloaromatic" compound f'sh'ould "be about 1- 3 0 by weight if a monohalog'eneompound is used; and preferably"ab0ut 5=20%;' but s'l'i'u'ld be somewhat lower such as 05-15% in t ase of a dihaloa'romatic"compound; erg. a dichlorstyrene, 1 in this case .the preferred P proportions being about 2 -10%", andeyn asnialle'r amount, e. g. ab'out 0.3-*10%-,-preferably-about'-1 5%"- iri the case or a trrha logenated arom'atic" com" pound. ln' otlier words; the genral 'g'uid for determining -the amount of haloaromatic oom" pound to be used is 'that the-iarithmetic product of the per i cent f haloaromatic compound tim'es volume of reaction liquid, after which the product is then washed one' or more times with water either as the original reaction mixture or dissolved in naphtha, benzene, etc. andcompletely separated from hydrolyzed catalyst, and finally the copolymer is separated from the solvent used --during the reaction or the naphtha or benzene subsequently added, this final separation being sired minor proportion of dior higher halogenated aromatic compound, a major proportion of isobutylene or otherlower'olefins, and, as a mutual solvent and copolymerization assistant, a minor amount of anunhalog'enated accomplished either by distillation or by precipitation if the polymer had not previously been precipitated during the catalyst hydrolysis step. If desired, a small amount of lubricating oil base stock may bev added to the copolymerization reaction mixture either before or during but preferably after the copolymerization, but before .separation of thevolatile solvent from the copolymer, in order to avoid subsequently having to polymerizable mono-olefinic aromatic com-.. pound such as styrene per se, alpha methyl sty-. rene, indene, dihydronaphthalene, etc. or a monohalogen substituted derivative thereof. In

such a case, the proportion of unhalogenated or monohaloaromatic compound should generally be about 1 -5 partsby weight for each 1 part by weight of -dior higher halogenated aromatic compounds.

The copolymerization is carried out under the general conditions described in U. S. Patent 2,274,749, but for the purposes of the present invention, the copolynierization should be carried out at temperatures below 50 0., preferably below --'70 C., e. g. 78 C., the temperature obtained when using solidified carbon dioxide as internal or externalrefrigerant, or 103 C. as obtained when using liquefied ethylene as refrigerant, and the copolymerization should also be carried out in the presence of a lower alkyl halide solvent, such as methyl chloride, ethyl chloride or methylene chloride, using about 1 to 10 volumes of suchsolvent per volume of liquid reactant. In order to efiect the copolymerization, onemay use either aluminum chloride or boron fluoride or other Friedel-Crafts catalyst, e. g. AlBra, TiCl4, etc., or various mixed catalysts,'e. g. AlBrzCl, AlClz'Br etc., or various catalyst complexes such as BFa-dichloroethyl ether complex etc. Some of these catalysts, such as A1013, areadvantageously'used in the form of a solution thereof in a solvent such as a lower alkyl halide, e. g., methyl chloride, ethyl chloride, and the like, this solution preferably being made by dissolving the AlCls in the solvent at the boiling point of the solvent or at room temperature or slightly elevated temperature, then cooling the resulting solution to or near the desired copolymerization temperature. A gaseous catalyst such as BFs maybe used either in the gaseous state by bubbling it through the reaction liquid, or may be used as a solution which may be made by bubbling the BE; into a solvent such as methyl chloride or ethyl chloride and then cooling the solution to the desired copolymerization temperature. V 1

In carryingout the copolymerization reaction, various procedures may be used, for instance one of the. simplest methods is to mix the two or more reactantsand the inert solvent, and then add the catalyst. p

After the copolymerization' reaction has been completed, ,which'generally requires only a few minutes, residual catalyst is hydrolyzed and removed by adding to the reaction mixture a substantial amount, such as about A0!) to deactivate the catalyst) to 10 (to also precipitate the polymer)" volumes of a lower alcohol such'as methyl or isopropyl alcohol, etc., or water or aqueous caustic soda, or mixtures thereofiper dissolve a dry copolymer in the lubricating oil base stock; this procedure facilitates the later incorporation of the copolymer into the final blend oil composition, because the concentrated solution containing about 10-50% or, so of co polymer-in a mineral oil basestock can readily be blended with a larger amount of mineraloil witharelatively light stirring. V.

The petroleum hydrocarbon fraction with which the above-described haloaromatic-olefin copolymer is to be compounded, may be any ofthe substantially non-volatileliquid or solid pe-. troleum fractions. For lubricating purposes, which is the primary objective of this invention,

the base stock should be; a mineral lubricating oil 7 derived from any of the normally available crude petroleum sources, such as paraflinic, naphthenic or mixed base :crudes, and the lubricating oil fraction used may have been separated'or refined by anyof the various methods known to the art, such as distillation, solvent extraction, etc., and may have been subjected to various purification treatments, such as clay contacting, acid treating, soda washing, etc., or any com-. bination of these or other known refining treatments. For special purposes such as for preparing hydraulic oils, etc., it is desirable to use a mineral oil base stock of a lighter boiling range, such as a gas oil. On the other hand, it is also. feasible to apply the invention to heavier ,peitroleum oils, such as cylinder oils, bright stock, etc., as well as normally solid petroleum fractions, such as asphalt, parafiin'wax, petrolatum, etc.-

The invention will be better understood from a consideration of the following experimental data:

EXAMPLE 1 10% by weight of parabromostyrene was mixed with by weight of liquid isobutylene, and 500 ml. of the resulting mixture was diluted with 1500'ml. of pure methyl chloride. This reaction mixture was then placed in a 4 liter copperreactorv which was held in a Dewar fiask. Liquid ethylene (about -2- liters) was added to the Dewar flask to act as an external refrigerant. Whenthe temperature of the active feed had reached 10 1 C., A1C13 catalyst solution consisting of 0.5 g. AlCls/IOO m1. CHaCl was added for three minutes at 28 cc. per minute. After a period of 10 minutes, the catalyst was killed. by the addition of 50ml. of dryv isopropyl alcohol. Theecpper reactor :was removed from the-liquid ethylene;

after the methylgchloride had evaporated the polymer was removed, washed with water, and air driedma A chemical analysis, of, thecopolymer showed 4.5% of bromine (-byParnBomb. analysis), which indicated that'the parabromstyrene had copoly;

Table I Vl-SQDSUZY 7 I. of Percent Oopolymer V. I Poly- 1 1 Polybutene of 45,000 mol. wt. made at 78 C.

The above data show that the parabromstyrene-isobutylene copolymer is quite unexpected- 1y superior to a corresponding polybutene in regard to viscosity index improving characteristics in a paraffinic mineral lubricating oil. It should be noted that not only are the V. I. improving properties greater, but also .the V. I. ceiling is substantially higher, because, as previously pointed out the V. I. ceiling of polybutene (regardless Emmett-s51 lv A copolymer was made from a 'mixture of 97 by weight of parachlorstyrene and 91% by weight of isobutylene, using the same procedure described in Example 1, and the resulting copoly mer, which showed 1.01%chlorine by analysis contained 3.95% p-Cl styrene, andhad an average molecular weight of about 50,000 and an intrinsic viscosity of about 1.7, was blended in several concentrations in the same type of paraflinic lubricating oil base stock as used in the test in Example 1, and the resulting blends were then tested for viscosity and V.'I. characteristics, with the following results: I

. Table III p Vlscosity(c.s.),

Percent Gopolymer V I v V.I

100913 .-v '?10 F.-. Y

The above data indicate that the parachlorstyreneiisobutylene copolymer showed almost the same'V. I.-increasing efiiciency as the corresponding parabrom co'poly when tested in 1% concentration, but the parabrom copolymer of Example 1 was superior to the corresponding-parachlor'copolyrner because of molecular weight and concentration) is in the general vicinity of 135 in such a-paraflinic lubricating oil; the corresponding ceiling for styreneisobutylene copolymers made with 5, 10, and 20% styrene at -101 0., appears to be about 140-142.

The parabrom copolymer gave a V. I. of 145; when used in a concentration of only 1.5%. EXAMPLE 2. 1

A tripolymer was'made b y copolymerizing a mixture of 70 gms. of liquid isobul yl'ene, 25 gms. of styrene, and 5 gms. of"dichloro'styrene which was a commercially obtained =mixture' probably containing a major proportion of 2-5 'dichlorostyrene. These reactants were diluted withf750 ml. of methyl chloride and the reaction mixture 5 was then polymerized at -"-90 C. by'feeding into the mixture for 4 minutes" a catalyst solution, consisting of 0.5 gm; of AlChper' 100 ml. of methyl chloride, at the rateof28 cc'. per minute. The resulting copolymer was recovered by "the same procedure as in Example 1 and was found to have an average molecularweight of about 41,000 and an intrinsic viscosity of about 1.0. Y c g This styrene dichlorstyrene- 'isobutylene tripolymer was then blended in 1% concentration in a naphthenic base mineral lubricating oil and tested for viscosity and V. I. characteristics, with the following results:

It is thus. apparentlthat e it produced a lesser increase in viscosity for any particular increase in .V. I.

v EXAMPLE 4 10 ml. of parachlorstyrene was added to 100 ml. of liquid isobutylene, and to the resulting mixture was added 500 ml. of methylchloride and 100 gms. of solid carbondioxide to serveas internal refrigerant and'to maintain a reaction temperature of -'78 C. To this reaction mixture was added 100 ml. ofa catalyst solution consisting of 0.8% of AlCla dissolved in methyl chloride. A polymer was formed as the catalyst was added. The product was washed with water and air dried, and the resulting copolymer was found to have a molecularweight of. about 14;,000. It was solublein lubricating;oi1.

In carryingout. this invention, it is alsopossible to condense the halostyrene-isobutylene copolymers with an alkyl halide having from. 5 to 30 carbon atoms per molecule. such as amyl chloride, dodecyl chloride, octadecyl chloride, etc., or to 'alkylate withyarious olefins, such as isobutylene, amylene, diisobutylene, 'etc. or to condense such copolymer-with saturated dihalohydrocarbons or alkylene dihalides, such as ethylenedichloride, dichlor paraffin Wax. etc., or to condense with mono-, di-, or higherbasic acyl halides such as acetyl chloride, stearyl chloride, succinyl chloride sebacyl chloride, phthalyl chloride and mixed products such as acid chlorides of coconut oil fattyacids, etc., or to react the copolymers ceedingly efiective in raising the ;V. Ll'ofa' thenic type lubricating oil base stock.

with various. mixed products containing mono and dihalogen substituted hydrocarbons. such. as a chlorinated paraffin W ax ,having a chlorine content of about 10-15%-. Such alkylation and condensation reactions may; not only be applied to the copolymers.described above whichare actually soluble in mineral. lubricating oil but also to similar'copolyinersbf even higher halogen content, such as thosemade" by .copolymerizing up to 5'0 or. :more oil a, monocniofstyrene with isobutylene,.vor' up to 30%."or. so. .cr a dichlorstyrene with isobutylene, which latter copolyrneri- 'r used in" Example 1, v

,2 V zation is carried out, in fthe presence of a third component consisting of styrene or an alkyl substituted styrene. To 100 'parts by'weightof chlorinated paraflin wax (10.5% chlorine) were added 25 parts 'by weight of isobutylene-p-Cl styrene copolymer. (The copolymer was made at '-103-'C. by the use of AlCls in CH3Cl catalyst, contained 20% by Weight of p- Cl styrene, and had a Staudi nger molecular weight of 32,000.) The mixture was taken up in 50 parts of kerosene (based onchlorinated wax) to effect solution. A1C13 was now added in an amount of 2% parts, and the mixture was agitated. Temperature was maintained at 90 F., during a reaction period of 12 hours and finally the catalyst was hydrolyzed by the addition of aqueous alkali. The product was added to an excess of 99% isopropyl alcohol to precipitate polymer.

EXAMPLE 6 The initial product as made in Examples 1 to 4 was further condensed with a dicarboxylic acid chloride. The second condensation was made as follows: About 100 grams of the wax condensation product were placed in 1,000 grams of tetrachlorethane as solvent. A1C13 (15 g.) was then added alongwith 10 grams of sebacyl chloride. Heatingwas continued at 80 C. for one hour. Catalyst was hydrolyzed just as before and the material was then removed fromv solu tion by adding to excess isopropyl alcohol, and tested with the following results:

Per Vis. A. S T. M. Cent Material Added to Oil (8. S.-U.) V. I Pour Point Adde 210 F. I 7 F.

(Blank O' 42. 9 100 22 Orig. copo1ymer.. 57.4 133 22 5 Wax cond. product of 50.0 136 0 copolymer. 5 Sebacylated wax cond. 48.8 3 139 5 prod. of copolymer.

The 'data n the" above table show-that the original p chlorstyrene isobutylene' copolymer (used as starting material in' Example 5), when used in 5% concentration, improved the V. I.

of the paraflinic lubricating oil base stockfrom 100 to 133 while raising the viscosity'at 210 from 42.9'1305724 seconds, but had no efiect on the22 F. pour point of the oil base stock. "The data also show that the conde nsation of that'copolymer, with'chlorinated parafiin wax (as dethe product, since in 5% concentration itnow produceda v. I, orise'a d did so'with @210 F. viscosity of only 10.8 seconds, and slightlyiurther w r dthg p r. p int d n; o," +15? F-; h pour depressingproperties are quite surprsing because'highmolecular weight linear type bydrocarbon polymers and copolymers per, se have no pour depressing characteristics at all, and it is dif ficult to impart su'chj properties" to 107 grams of *p-Cl-styrene-isobutylene -copolymer (M. W; '(Sta'udinger) was "18,400 and contained 12.8% combined p-Cl'styrene)" were added to 600 cc. of tetrachlorethanaand' then 7.2 g. A1C13 were added to-the solution. At 25, 38 grams of'amyl chloride were added. The temperature was increased to '120-125" F. The total time of reaction was 5 hours, the mixture being well agitated. The "reaction was' kille'd'bythe addition of 20 cc. of isopropyl alcohol. Solvent was removed from the condensation product by evaporation. Total weight of the water-washed and dried alkylated polymer was 122 grams. Staudinger M. W. of this plastic and elastic product was 12,100, and it was soluble in benzene, toluene and mineral oil. The sample was blended 1 in a parafiinic lube oiland tested'for V. I. and

pour depressing properties with the followi g results:

This example indicates that such a hlorstyrene-isobutylene copolymer-can be alkylated in spite of its high molecular weight and, in spite of the presence of the chlorine on the aromatic nucleus of the styrene, both of whichfactors tend to reduce the susceptibility of a material to alkylation with alower alkyl halide; Such alkylated halogen-containing copolymers are new products. For use as lubricatingoil additives, this feature of the invention can be more advantageously applied either to copolymerscontaining the same or lesser. contentof halostyrene but polymerized to a much higher molecular weight (e. g. 30,000'or 40,000 or-higher), by use of :lower temperature, eg, :103,.:C., or stronger catalyst etc., or by applying the alkylation toa copolymer of similarly moderately --high' molecularv weight .(e. -g.- 10,000 tov 20,000 oraso) but containing a greater percentage of halogen.

By comparing Examples'5 and Ty'it is noted that mere alkylation of chlorstyrene isobutylene copolymer with amyl chloride (Example 7) does not impart pour; depressing characteristics: to the copolymer structure, whereas, (Example '5), condensation with chlorinated parafiin wax .of 10% chlorine (which containssome;monochlor and some dichlor wax .moleculesyq does.impartpour depressing characteristics... This may be-due to the combined effect of alkylation with higher alkyl groups (by the monochlor wax) and'some interlinking (bythe dichlor wax). A

' EXAMPLElBf" A copolymer of isobutylene and styrene was prepared in accordance with U. S. Patent 2,274,- 749. Temperature of polymerization was 101 C. and .A1C13 methyl chloride catalyst was used. Another copolymer was prepared or iso'butylene and parabromstyrene in accordance with Example 1. In each case the yield was about by weight based on the monomers. The copoly mers were dissolved, each in difierent samples of a I paraifinic mil'leral lubricating oil base stock having a visczosityv of'43 seconds, 'Saybo1t Universal at 210 F. and 11 2,,viscos ity i dex'. nhalo 1% styrem? 1% Parabromisobutylene tylenfi Thus blended to the same viscosity the halogenated product resulted in a'blend with a higher viscosity index, clearly indicating a patentable improvement over the unhalogenated product. The methods used to polymerize the two copoly mers tested,were the same. i

In preparing lubricating compositions according tothe present invention, in addition to using a mineral lubricating oil base stock and a V. I. improving amount of about 05-20%, preferably about 1-10%, of a high molecular weight haloaromaticolefin copolymer as described above, one may also use minor amounts of other known lubricating oil additives, such as dyes, oxidation inhibitors, sludge dispersers, pour depressors, grease-forming soaps, lubricity agents, corrosion inhibitors, detergent-type additives, anti-foaming agents, extreme pressure additives, etc.

This application is a continuation in part of the co-pending application, Serial No. 708,945, filed November 9, 1946, now abandoned.

It is not intended that this invention be. limited to the specific materials and conditions which have been recited merely for the sake. of illustration, but only by the appended claims.

We claim:

1. A process for the preparation of lubricating oil additives which comprises condensing with a halogenated aliphatic hydrocarbon containing from 5 to 30 carbon atoms a copolymer of parachloro styrene and isobutylene in the presence of a Friedel-Crafts catalyst, said copolymer containing from about 1.0% para-chloro styrene having a molecular weight of more than 14,000, and having been copolymerized at a temperature below about 50 C. in the presence of a Friedel-Crafts catalyst.

2. A process for the preparation of lubricating oil additives which comprises condensing with a chlorinated paraffin wax containing from to chlorine, a copolymer of para-chloro styrene and isobutylene in the presence of a Friedel- Crafts catalyst, said copolymer containing from about 1.0% to about by weight of parachloro styrene, having a molecular weight of more tha 14,000, and having been prepared at a temperature below about C. in the presence of a Friedel-Crafts catalyst.

3. Aprocess according to claim 2 wherein the condensation reaction is carried out at a temstyrene-Isobuto 30% by weight of 10 perature of about F. for a period of time of about 12 hours.

4. A process for the preparation of lubricating oil additives which comprises condensing with amyl chloride a copolymer of para-chloro styrene and isobutylene in the presence of a Friedel- Crafts catalyst, said copolymer containing about 1.0% to 30% by weight of para-chloro styrene, having a molecular weight of more than 14,000, and having been copolymerized at a temperature below about 50 C. in the presence of a Friedel- Crafts catalyst.

5. An improved lubricating oil additive which consists essentially of a Friedel-Crafts condensation product of a halogenated aliphatic hydrocarbon containing from 5 to 30carbon atoms and a copolymer of parachloro styrene and isobutylone, said copolymer containing from 1.0% to 30% by weight of para-chloro styrene, having a molecular weight of more than 14,000,'and, having been copolymerized at a temperature below about -50 C. in the presence of a Friedel-Crafts catalyst.

6. An improved lubricating oil additive which consists essentially of a Friedel-Crafts condensa-' tion product of a chlorinated paraffin wax containing from 10% to 15% chlorine and a copolymer of para-chloro styrene and isobutylene, said copolymer containing from 1.0% to 30% by weight of parachloro styrene, having a molecular weight of more than 14,000 and having been copolymerized at a temperature of below about 50 C. in the presence of a Friedel-Crafts catalyst.

7. An improved lubricating oil additive which consists essentially of a Friedel-Crafts condone. sation product of amyl chloride and a copolymer containing from 10% to 15% chlorine and a copolymer of para-chloro styrene and isobutylene, said copolymer containing from 1.0% to 30% by weight of parachloro styrene, having a molecular weight of more than 14,000 and havingbeen copolymerized at a temperature of 50 C. in the presence of a Friedel-Crafts catalyst.

JOHN D. GARBER.

DAVID W. YOUNG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 2,479,450 Young et al Aug. 16, 1949 below about 

1. A PROCESS FOR THE PREPARATION OF LUBRICATING OIL ADDITIVES WHICH COMPRISES CONDENSING WITH A HALOGENATED ALIPHATIC HYDROCARBON CONTAINING FROM 5 TO 30 CARBON ATOMS A COPOLYMER OF PARACHLORO STYRENE AND ISOBUTYLENE IN THE PRESENCE OF A FRIEDEL-CRAFTS CATALYST, SAID COPOLYMER CONTAINING FROM ABOUT 1.0% TO 30% BY WEIGHT OF PARA-CHLORO STYRENE HAVING A MOLECULAR WEIGHT OF MORE THAN 14,000, AND HAVING BEEN COPOLYMERIZED AT A TEMPERATURE BELOW ABOUT -50* C. IN THE PRESENCE OF A FRIEDEL-CRAFTS CATALYST. 